Subject 17A
by MamasLittleCat
Summary: Subject 17A is a human who was experimented on by W.D Gaster. She has magical outbursts due to her magic being so unstable from a couple pieces of two monster's souls that were forcefully merged with hers. Frisk and Chara try to keep it a secret, but can they for long? Chara and Frisk are both girls. (I know this isn't the best OC, but...)
1. Chapter 1

W.D Gaster received his first test subject, a small human from the surface. Is it a child? Most likely. The child had short, flowing blond hair to her shoulders. She has been put in her small cell until further notice. King Asgore and Queen Toriel did not like this test very much, but Gaster assured them that the girl would come to no harm. Yet. After twelve hours, the child opened their eyes. Her eyes were as blue as the sea, shining as she observed her surroundings. The two have made eye contact, her curiosity intriguing. He labeled her Subject 17A, and that is what she was called. As she grew older, Gaster started noticing that the girl started to mimic his movements, behavior, and language. After observing her for a while, he decided to do something that may be risky. After many troublesome attempts, he managed to take a piece of his soul and forcefully attach it to her human soul of patience. He tried to see if she could open the barrier now. _Failure._ Gaster scribbled down on his clipboard. Determined to try and set monsters free, he grew reckless. He forced a monster's soul to break and forced it to the human's soul. Not even an hour later, she had an outburst of magic, destroying a few of Gaster's possessions. As she looked around, he saw that her eyes were replaced with ones like his own, glowing vividly. When he should've been terrified of this monster that he created, he was fascinated by how much magic surged through her. Quickly scribbling down his observations, he tried to usher her to the barrier. _Maybe this is it,_ he thought. _Maybe if she could do another outburst of magic like that, we may be able to leave the Underground forever!_ Little did he know that her magic was very unstable, and that she could not control it. She surged with magic, knocking Gaster to the floor, his glasses flew off of his face. Before he could stop her, she had created a portal and left.


	2. Chapter 2

Frisk and Chara were walking down the street. The pretty houses were lined up in neat and tidy little rows. Toriel's house was up ahead, housing herself, Frisk, Chara, and the Skeleton Brothers, Sans and Papyrus. As they walked along, there was a rustle in a nearby shrub. Frisk and Chara turned their heads in the direction of 's house with his neat front yard. The hedge in front of his house was shaking as a portal opened up. It closed after something had come out and landed behind the bush. Chara and Frisk hurried to the hedge, quickly looking both ways before crossing the street. Chara looked over the neatly trimmed hedge to see someone behind it. Frisk copied her movements, seeing a blond-haired girl, her eyes blue like the sea. Frisk looked at her questioningly while Chara just stared at her, waiting for something. The girl quickly took in their faces and the scenery around her. She began to speak gibberish to Frisk. "Hmm." Chara thought hard, as though translating what the girl was saying. "You don't know where you are? Can you understand me?" Chara asked the girl. Frisk realized that the girl was wearing something like a hospital gown, and not any actual clothes. The girl looked at Chara as though she had questions. She began to speak the same gibberish of weird noises. Chara nodded. "I see. So you don't understand English..." "Wait, you understand what she's saying?!" Frisk asked quickly. Chara nodded again. "Yes. She speaks Wingdings. I wouldn't think many knew how to speak it, let alone understand it." Chara responded. Frisk looked back at the girl. "Ask what her name is!" Frisk whispered into Chara's ear. Chara nodded once more and spoke the same language as the girl. The girl responded in Wingdings as Chara looked back at Frisk. "She says she's 'Subject 17A.' That must be what she was called at the lab." Chara added quickly. "The lab? Like, the True Lab?" Frisk questioned. "Yes. She must've been one of the first, but why was she called 17A? I wonder..." Chara's voice trailed off. Frisk checked the time using a small pocket watch Sans lent her. "Ahh! Toriel's going to flip out! It's almost four o' clock! Chara, we have to go!" Frisk said urgently. Frisk started to pull her arm when she realized she wasn't going to budge. Frisk stopped her attempt and gazed back at the girl. "What're we going to do with her," Chara asked. "We can't leave her here." Frisk stared at the girl for a moment longer before an idea hit her. "Maybe we can invite her to the house for a sleepover! Say she's from our school. It may be suspicious if she looks like she's from a hospital, though." Frisk added. The two pondered this for a moment. "Well, I _do_ have a spare sweater she could borrow." Chara remembered. She slid the backpack off her shoulder and onto the concrete sidewalk. She reached into her back and out of it emerged a black sweater with two pink stripes like Frisk's. Frisk pulled out a spare pair of jeans out of her backpack and handed them to the girl. The girl grasped them.

The girl looked at the sweater and pants curiously. Chara and Frisk realized simultaneously that she doesn't know how to dress herself. Reluctantly, they dressed her while she examined the process. Frisk checked her pocketwatch. _"Ten minutes until five, Chara! TEN MINUTES!_ Oh gosh, Toriel's probably worried sick!" Frisk said as she rambled on about how much trouble they'd be in while Chara talked to the girl. "Do you have a real name?" She said to her in wingdings. "No, I do not know what my name is besides Subject 17A." She responded. Chara sighed as they walked on. "Don't say anything to the people you'll see. Don't say anything around them, they'll ask questions. If they do, Frisk and I should be able to step in." Chara told her. The girl nodded. After pondering for a moment, Chara stopped dead in her tracks. Frisk noticed as she turned around. "Wait, if anyone asks what her name is, we can't say 'Subject 17A!' That'll make everyone ask questions! We have to come up with a name for her." Chara said to the other two. She repeated her words in Wingdings for the girl, then began to think. After a moment of thinking, "Maybe her first name could be Addyson. Because 17 _A_?" Frisk suggested, putting emphasis on the A. Chara nodded. "That'll do. But what about her last name? _What's the seventeenth letter of the alphabet?_ " Chara asked herself aloud. After a second of thinking, Frisk piped up. "Q is the seventeenth letter of the alphabet, so maybe her last name could be Quinton!" Frisk said. "Addyson Quinton is a great name. It'll do just fine." Chara announced. The headed to Toriel's house, silently praying that Toriel would even allow the girl to stay.


	3. Chapter 3

Frisk and Chara hurried along to Toriel's house, Addyson following them. Once they got to the door, Chara turned to the girl. "When Toriel looks at you, wave at her." She told her in Wingdings. Chara waved at Addyson to give her an example. She mimicked her movements and nodded. Frisk knocked three times on the light purple door, the royal crest painted on it. Before they knew it, a slightly irritated Toriel answered the door. "Oh my goodness, I was so worried! Where have you been?" "Uh.. We met a new friend!" Frisk said, moving aside so she could see the girl. Once Toriel looked at her, Addyson stared back at her.

 _"Lady Toriel, I assure you that the girl is okay." Gaster told the uneasy Queen. She walked past the girl's cell, her worried eyes still upon the girl._

* * *

Addyson snapped back to reality and waved at Toriel. "Oh! I see." Toriel turned her gaze back to Frisk as they spoke. "Can she stay the night? Please?" Frisk asked. "As long as her parents are okay with it, sure!" Toriel beamed. Chara led Addyson to her bedroom, but was stopped by Sans. "hey, where've you two been? met a new friend?" He said as he nodded toward Addyson. "Yeah. Her name's Addyson." She quickly told him before she started to walk on. She made it up the stairs without any more questions. Frisk quickly went up the stairs and into the room she shared with Chara. Once she closed the door, she turned to Chara. "We can't keep her a secret forever. But, while she's here," Frisk said, turning to Addyson. "We can teach her English!" Chara nodded, translating Frisk's idea to Addyson. She looked excited to hear this so much so that her eyes glowed green. Chara and Frisk jumped back in shock. _"Your eyes are glowing green!"_ Chara whisper-yelled to Addyson in Wingdings. As a questioning look appeared on her face, her eyes stopped glowing. After two minutes of hesitation, Chara whispered to the other two. "Let's just go to sleep and sort things out in the morning." It was Friday, so Chara and Frisk didn't have school the next day. As they pulled out a sleeping bag for Addyson, she was pondering her emotions.

 _Addyson was beaming at the scientist. He also smiled, his eyes glowing green. "You are happy. It's good to be happy sometimes." He told her as he walked over to two slices of Butterscotch Cinnamon Pie. Gaster took out a platter and put a slice on the plate. He handed it to her. She held the platter and examined the piece of pie on it. "I hope you do not mind the cinnamon. Since you do not know what it is, I didn't know what to tell her when she asked. Her name is 'Toriel.'" He told her the name in English. "She made you this pie." As he handed her a fork, she attempted to pronounce the name. "T-Tur... Tori... Toril.. Toreil.. Toriel!" She bounced up when she was able to pronounce it. Her eyes glowed a bright green, her eyes twinkling. She ate the pie, savoring every bite of it._

* * *

Addyson laid down in her sleeping bag, closing her eyes as she drifted off to sleep. Chara and Frisk were snuggled in their blankets as they too fell asleep.

Sans sat on the couch in the living room. Flowey was sitting in a flowerpot on the coffee table in front of the sofa. Sans was surfing through the TV channels before deciding to go to Netflix. Papyrus left the Kitchen and headed upstairs, yawning. "GOODNIGHT, DEAR BROTHER! I SHALL SEE YOU TOMORROW MORNING! PLEASE DO NOT STAY UP TOO LATE! NYEHEHEHEHEH! Papyrus told his brother from the stairs. He walked into his room and shut the door softly.

He opened it again, saying a final "HEH!" before shutting the door. Sans sighed as he went through the movies. He settled on a Comedy Show before Toriel left the Kitchen. She yawned. "Goodnight, Sans." She told him before she started up the stairs. "Oh, and also check on the girls after ten to make sure they're asleep. Can't have them up past twelve!" She added before disappearing into her room. "sure, tori. good night." Sans responded. He turned back to his TV, slowly falling asleep. When he woke up, it was fifteen minutes until eleven o' clock! Sans woke up, disturbing Flowey in the process. " _HEY!_ I'm watching this show. This dude's pretty funny!" Flowey added. "You've really gotta stay up and watch him!" Sans rushed upstairs to the girl's room. A mysterious light was seeping out from under the doorway. _Hmm._

* * *

Addyson was woken up by something bumping lightly into her shoulder. She shrugged it off. It decided to start bumping into her side. Addyson turned over and opened her eyes. A little Gaster Blaster was hovering before her, the eyes had cracks similar to the scientist's. The small blaster looked at her playfully. As she sat up, she realized there were three hovering around her. She gazed at them. Before long, one of them playfully tackled her, nipping gently at her face. She giggled very quietly, trying not to disturb the other two girls in the room. She played quietly with the blasters, petting them and letting them playfully nip at her. As she was playing fetch with one using a rubber ball she had found, Sans opened the door. The three small Gaster Blasters turned their heads, as did Addyson.

Sans observed the room, his eye sockets landing on Addyson. Her eyes were glowing white, showing eyes like Gaster's, but no sockets. Just white. As they made eye contact, his eyes disappeared from her face, leaving her normal sea blue eyes. Her eyes suddenly glowed purple. _She's scared,_ He thought. "what..." Addyson quickly hid herself in her sleeping bag, whispering. The small blasters disappeared, leaving Frisk and Chara asleep, Addyson, and Sans. He drew closer to her sleeping bag to hear what she was whispering. He recognized the language immediately as Wingdings. "No no no no no no! He's saw me... He's seen me! What am I going to do?" She whispered quickly. Sans quickly pulled down the sleeping bag that was covering her face. "Please don't be mad.. Please... I blew it!" She whispered quietly. Tears trickled down her face as she turned over to her side. Her eyes weren't glowing. Sans got up and backed away, closing the door behind him. He plopped himself down on the couch. "they're going to have to explain some _things_ tomorrow." He whispered to himself.  
"Who are you talking to?" Flowey asked him. Sans didn't answer. He sat there, pondering any reasonable explanations.


	4. Chapter 4

When Addyson woke up, light was streaming through the window. _He saw me. He heard me. Oh, what trouble did I get Chara and the other girl into?_  
Chara and Frisk woke up shortly after each other. "Good morning" Chara yawned. Frisk hopped off her bed and made her way to the door. Addyson was nervously sweating, her eyes glowing purple. Chara noticed as she got off her bed. "What's wrong?" Chara asked her in Wingdings. "He saw me. He walked in and saw me with those small blaster things." She responded in Wingdings. "Who?" Chara asked worryingly. "The skeleton." She answered quickly. Chara's eyes widened as she turned to meet Frisk's gaze. Frisk's face had the _what-trouble-did-we-get-into-now_ look, but she wiped off the expression as she left the room. Chara turned back to Addyson as she held out her hand. "Don't be scared. It'll be okay."

 _Addyson cowered in the corner of her cell. Gaster had walked into the cell, pushing his glasses up his face. He bent down and held out his hand to the girl in the corner. "Don't be scared. It'll be okay." His eyes were filled with kindness, his face cracked but caring. The girl took his hand and left the cell with him._

* * *

Addyson snapped back to reality and took Chara's hand. She let Chara help her up and lead her out of the room. They went down the stairs, being careful not to wake up Sans sleeping on the couch. They sat at the Dining Room table while Toriel and Papyrus made breakfast in the kitchen. Flowey was in-between Frisk and Chara's seats on the table. Flowey leaned into Frisk and whispered. "I think one of you three are in trouble with Sans. He seemed _pretty_ jumbled up after he checked in on you guys last night." Frisk straightened up when he said this, sweating a little. Chara had overheard and looked worried, but she wiped the expression off her face once Toriel put a Bacon and Cheese Omelet on her plate. Once she put toast with butter on the side of her plate, Toriel asked the girls a question. "Did you all sleep well?" "Yes." Chara and Frisk responded while Addyson nodded. Frisk had pancakes with maple syrup and butter on top. Frisk dipped her crispy bacon into the maple syrup while Addyson ate a bowl of oatmeal. "Thank you, Toriel." Addyson said in English. Frisk and Chara quickly looked up at her, shocked. "You're welcome, child. Oh! I never quite caught your name. What is it?" Toriel beamed. The girl smiled. "Addyson." Chara saw her eyes spark green, but she seemed to control it. Once Toriel turned back to the kitchen, Flowey turned to Chara. He asked, "Why was it such a surprise that she said something in English? I couldn't help but notice you two's expression." Chara straightened up at this question. "I dunno. She just hardly talks." She responded quickly. Flowey looked like he had questions, but he kept his mouth shut. Chara, Frisk, and Addyson pushed in their chairs as they left the table. Outside of the dining room, Sans was waiting by the doorway. "could i ask you three something?" He asked. His pupils had disappeared, leaving his eye sockets to give a serious look. "S-sure." Chara replied. They all took a seat on the couch.

"can one of you give me a reasonable explanation as to why this addyson," He nodded to Addyson. "can summon gaster blasters and speak wingdings?" The four sat in silence for a moment. "No." Frisk replied hesitantly. Sans sighed. He inhaled and continued. "where did you even find her in the first place?" Frisk inhaled deeply. "Well, we were on our way home and there was this weird portal so we went to it and she popped out." Frisk said very quickly, all in one breath. "I think she somehow traveled through time and space." Chara noted. Sans looked stunned by this assumption. "where would that answer even come from?" He asked. "Well," Chara replied, standing up. "You would've heard of her before if she was a test subject- I mean-" Chara accidentally let it slip. Addyson's eyes widened. Sans looked very disappointed at the fact that they kept this a secret. He sighed once more. "we can't know that for sure. if she was, what was her subject name?" "Subject 17A." She responded in Wingdings. "He tried to use me to break the barrier. Before I knew it, I was behind a bush where Chara and Frisk found me." She said Frisk's name in English, which took some skill. Sans stood up, using his magic to turn her soul blue. When he saw it, he was alarmed. Her soul was half patience, two pieces of separate monster's souls forced together. This sudden action made Addyson panic, as she could not move. The other two parts of her felt in danger, so he only had a moment to observe it before she bursted with magic. Her face looked like the scientist's again, glowing white with no pupils. The pain was unbearable, like she was being ripped apart.

 _She was suspended in midair, breaking things around her. The two other parts of her soul tugged, the magic bursting outwards unstable. The scientist's face was full of curiosity and amazement. "Hahaha! They said it was impossible, they said it couldn't be done, but I've done it! I've had a breakthrough!" The girl was in sharp pain. Make it stop, make it stop! Her mind screamed. When it ended, she fell to the floor with a hard thud, making the world go dark._

* * *

Sans quickly stopped his magic, but the girl was still bursting with magic. She waited and waited. She was patient. _It'll stop eventually. It always stops.  
_ She was being torn apart from the inside, the two pieces of soul trying to escape. After a couple more minutes, it stopped. She was suspended in the air for a moment more, her face morphing back her her own. Her shirt, as everyone in the living room noticed, had changed. It went from her usual black sweater with two pink stripes to a pink shirt with one thick black stripe during her magic outburst. As she was midair for a moment longer, it changed back to her old sweater. She lost consciousness before she fell out of the air. Sans quickly used blue magic to make sure she didn't fall to the floor and gently rested her on the sofa. Everyone let out an exhale of relief and sat on the couch, careful not to sit on the unconscious girl. After a moment of awkward silence, Frisk asked quietly. "Please don't mention this to anyone else." "yeah, i won't." Sans replied.


End file.
